The present invention relates to a method and apparatus for use in network acquisition for cellular communications devices.
Cellular communications devices such as cell phones, have become increasingly popular and widely adopted and in many instances have become the prime means of communication both for business and domestic requirements
As such usage becomes more widespread, potentially disadvantageous and limiting features of such devices become more apparent. For example, when a cell phone is first turned on, an acquisition procedure needs to be conducted so that the cell phone can acquire the appropriate communications network and subsequently take part in a communications exchange over that network. The period between turning the cell phone on and actually acquiring the network does not generally go unnoticed by the user and comprises dead time as far as the user is concerned since no other operations over and above network acquisition are conducted during that period. The longer the time period required to acquire the network, the more likely this period is to be noticed by the user and so as to lead to potential irritation. Also, network acquisition procedures require the cell phone handset to expend a significant amount of power relative to power requirements arising merely for communication procedures.
Indeed, in view of the different mobile communication modes that have arisen, and the subsequent requirement for cell phone handsets to offer dual mode, or indeed multimode, operability, it will become increasingly necessary for each handset to search on more than one mode. Thus potential delays m network acquisition, and related user irritation, could become more frequently experienced. As explained further below network acquisition requires a search through a set of frequencies—generally defined by a frequency band in an attempt to identify the most suitable cell of a network. With dual mode operation, there will be multiple sets of frequencies to search through in order not only to find the most suitable cell, but also the most suitable network given the at least dual mode operability of the handset.